Dual wall can end



Dec. 24, 1968 J, 5 oz ET AL. 3,417,898

DUAL WALL CAN END 2 Sheets-Sheet 1 Filed Oct. 20, 1965 INVENTORS JOHN S. BOZEK EJOHN S. SONG Dec. 24, 1968 J 5. BOZEK ET AL DUAL WALL CAN END 2 Sheets-Sheet 2 Filed Oct. 20, 1965 INVENTORS JOHN S. BOZEK United States Patent 3,417,898 DUAL WALL CAN END John S. Bozek, Chicago, and John S. Song, Addison, Ill., assignors to Continental Can Company, Inc., New York, N.Y., a corporation of New York 7 Filed Oct. 20, 1965, Ser. No. 498,365 7 Claims. (Cl. 220-66) ABSTRACT OF THE DISCLOSURE This disclosure has to do with a can end particularly adapted for use as a part of a can which is subjected to high internal pressures. The high internal pressures react against the end panel of the can end and tend to outwardly bow the end panel. This bowing reaction of the end panel results in a radially inwardly directed force being applied upon the chuck wall which, when the pressure is sufiicient, pulls the chuck wall away from the can body and opens the double seam. This is prevented by providing the can end with a double wall construction between the chuck wall and the end panel, which double walls projects axially inwardly into the interior of the associated can body.

This invention relates in general to new and useful improvements in can ends, and more particularly to a novel can end of the type which is readily openable utilizing a punch type opener and at the same time will resist high internal pressures.

This invention particularly relates to can ends for use as components of cans adapted to have packaged therein a product under high gaseous pressure with the can ends being formed of as light weight metal as possible and at the same time having suflicient strength to resist bulging and buckling under pressure. The can ends of this invention are particularly adapted for use with high pressure beverage cans used for carbonated soft drinks.

The manufacture of can ends for high pressure beverage cans presents two conflicting problems. In the first place, the can end must be readily openable by all users utilizing conventional openers, such as the puncture type openers. On the other hand, the can end must have suflicient strength to resist bulging and buckling under pressure. It has been found that bulging and buckling under internal pressure has resulted only secondarily from the actual stretching and deformation of the end panel and primarily from the radially inwardly deformation of the side wall or chuck wall of the end panel due to the radial pull exerted thereon by the end panel as it is forced axially outwardly by the pressure within the associated can. In accordance with this invention, it is proposed to overcome the bulging and buckling of can ends for high pressure beverage cans within the range of pressures normally found in such cans by reinforcing the side wall of the can end in a manner which in no way interferes with the application of the can end or the opening thereof.

In accordance with this invention, it is proposed to make the side wall of the can end of a double wall construction. It has been found that by sharply bending the can end at the lower end of the conventional side Wall or chuck wall and doubling the thickness of the side wall 3,417,898 Patented Dec. 24, 1968 ice at the lower portion thereof, the resistance of the side wall to radially inwardly directed deflections is greatly increased.

In view of the foregoing, it will be apparent that, simply stated, the object of this invention is to provide a novel can end for high pressure beverage cans which is made of a minimum thickness metal to facilitate the opening of the can and at the same time having sufiicient strength to resist bulging and buckling under the internal pressure within the can.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawings:

FIGURE 1 is a fragmentary top perspective view of a can having one end closed with a can end formed in accordance with this invention, an intermediate portion of the can end being broken away and shown in section to clearly illustrate the details thereof.

FIGURE 2 is a bottom plan view of the can end prior to the application thereof to the can body.

FIGURE 3 is an enlarged fragmentary sectional view showing the outer peripheral portion only of the can end of FIGURE 2 after a first forming operation.

FIGURE 4 is a view similar to FIGURE 3 showing the can end after the second and final forming operation.

FIGURE 5 is a view similar to FIGURE 3 showing a slightly modified form of can end.

FIGURE 6 is a view similar to FIGURE 4 showing the modified can end after the forming of a second operation on the can end structure of FIGURE 5.

FIGURE 7 is a fragmentary top perspective view of a can having still another form of can end attached thereto.

FIGURE 8 is a bottom perspective view of the can end of FIGURE 7 prior to the seaming thereof to a can body.

FIGURE 9 is an enlarged fragmentary vertical sectional view taken through a peripheral portion only of the can end of FIGURE 8 after a first forming operation.

FIGURE 10 is a view similar to FIGURE 9 and shows the can end after a second forming operation; and

FIGURE 11 is another view similar to FIGURE 9 and shows the can end after a third and final forming operation.

Referring now to the drawings in detail, it will be seen that there is illustrated in FIGURE 1 a high pressure beverage can which is generally referred to by the numeral 15. The beverage can 15 includes a conventional can body 16 which has secured to at least one end thereof a can end which is generally referred to by the numeral 17 and which is formed in accordance with this invention.

Referring now to FIGURE 4 in particular, it will be seen that the can end 17 includes a conventional curl 18 for facilitating the securement of the can end to the can body 16 by means of a conventional double seam, such as the double seam 20 illustrated in FIGURE 1. The curl 18 has integrally joined to the inner edge thereof a side wall or chuck wall which is generally referred to by the numeral 21. The side wall 21, in turn, has integrally joined thereto an end panel 22.

The side wall or chuck wall 21 differs from conven- 3 tional side or chuck walls in that it is of a double wall construction. It is to be noted that the side wall 21 includes an outer side wall 23 and an inner side wall 24. The side walls 23 and 24 are connected together along radius of the bend, which radius is referred to by the letter D varies from 0.00 inch to 0.025 inch.

Comparative tests have been made with can ends formed in accordance with this invention and other known their bottom edges by a relatively sharp bend 25. 5 can ends with the following results:

Bulge Bulge recovery Buckle Opening Contour Thickness (p.s.i.), from 82 p.s.l., (p.s.i.), force, lbs.,

average average, average average percent Conventional 0.0099 steel 81 Over 52 99 16.5 Soft top 0.0145 aluminum 71 3O 84 11.5 Felather tguch Patent No. 0.0094 steel. 74 51 110 12. 5 Dual wall. --do 14a 12. 55

Do 0.0082 steel 101 106 9.5

1 None at 143, falls by buckle. 2 Not applicable. The outer side wall 23 is integrally connected at its Referring now to FIGURE 7 in particular, it will be upper edge to the curl 18. The outer side wall 23 slopes seen that there is illustrated another form of beverage downwardly and radially inwardly from the curl 18 with 20 can which is generally referred to by the numeral 32. The the angle of slope being between 7 and 10. On the beverage can 32 includes a conventional can body 33 other hand, the inner side wall 24 is cylindrical. The bend which has at least one end thereof closed by means of a 25 has an internal radius B of approximately 0.012 inch. can end which is formed in accordance with this inven- Referring now to FIGURE 3 in particular, it will be tion and is generally referred to by the numeral 34. The seen that the can end 17 is formed in a two-stage opera- 25 can end 34 is secured to the can body 33 by means of a tion. The can end is initially drawn to be relatively deep conventional double seam 35. and includes a side wall 26 which is integrally connected The can end 34 is formed in three progressive steps. at its upper end to the curl 18 and which is connected In the first step, the can end 34 is shaped to include a by means of a relatively large radius 27 to a deeply reperipheral curl 36, a relatively deep side wall 37 and an cessed panel 28. The side wall slopes downwardly and end panel 38 joined to the side wall 37 by a radius 39. radially inwardly at the angle A which corresponds to In a second forming operation, the radius 39 and a lower the final angle of slope of the outer side wall 23. portion of the side wall 37 are deformed to define a dou- Then in a subsequent forming operation the panel 28 ble wall side wall or chuck wall which is generally reis moved axially upwardly and the radius 27 is deformed, ferred to by the numeral 40. At the same time the end toegther with a lower portion of the side wall 26 to panel 38 is moved axially upwardly. The contour of the form the inner side wall 24 and the sharp bend 25. The curl 36 remains unchanged. At this time the double wall panel 28, which is moved upwardly, becomes the end side wall 40 includes an outer side wall 41 and an inner panel 22 and may be provided with an upwardly directed side wall 42 which are joined at their lower edges by a reinforcing bead 29. relatively sharp bend 43. The outer side wall 41 slopes The can end 17 is applied to the can body 16 utilizing downwardly and radially inwardly at a slight angle a conventional double seamer and the curl 18 is rolled which may range from 4 to 12. The inner side wall 42 together with the flange (not shown) of the can body is cylindrical. to form the double seam 20. When the can 15 is utilized In a third operation, the arc of the bend 43 is increased as a. beverage can, particularly for carbonated soft drinks, and the inner side wall 42 is outwardly flared so that it there is an extremely high pressure within the can, the 45 now slopes upwardly and radially outwardly and the uppressure being even greater than that existing in beer per portion of the inner side wall 42 is adjacent to or cans. This pressure, of course, tends to move the end in contact with an intermediate portion of the said wall 41. panel 22 axially away from the can body 16. Inasmuch When the inner side wall 42 is flared, the end panel 38 as the peripheral edge of the end panel 22 is restrained moves downwardly very slightly. The shape of the can by the side wall 21, except for the slight bowing or bulgend 34 at the end of the third operation, as shown in ing thereof due to the slight deformation of the metal of FIGURE 11, is the final section of the can end. the end panel 22, the dual wall construction restricts the The can end 34 is double seamed to the can body axial movement of the end panel 22 both with respect to 33 in the same conventional manner as that described buckling and bulging. In order for bulging and buckling above. It will also be understood that the specific shape to occur to any extent, it will be apparent that the side of the can end 34 .provides the same beneficial effects as wall 21 will have to be materially deformed. It has been those set forth above. In fact, the can end 34 is stronger found that the double wall construction of the side wall because of the specific configuration of the double wall 21 resists undue bulging and buckling of the end panel side wall 40. On the other hand, a third operation is re- 22 under the pressures normally found in carbonated soft quired to form the same and it is less desirable for this drink cans even though the metal of the can end 17 is reason only. It is also pointed out here that the end panel of a much thinner gauge than that normally utilized in 38 is illustrated as being plain. If desired, it may be proforming can ends for high pressure beverage cans. Bevided with a rib, such as the peripheral reinforcing rib cause of the metal of the can end 17 being thinner than 29 of the can ends 17 and 30. that normally utilized, the can 15 may be more readily We claim: opened utilizing a conventional punch type opener. Thus, 1. An easy opening can end for cans subjected to high the specific structure of the can end 17 provides for a internal pressures, said can end having a high strength greater strength while at the same time being easier to to material thickness ratio and comprising means for open, forming a double seam including a peripheral curl and a In FIGURES 5 and 6 there is illustrated a modified side wall connected to the curl, an end ,panel, and a dual form of the can end of FIGURES 1 through 4. This modi- Wall connecting the side wall to the end panel, said dual fied can end is generally referred to by the numeral 30 wall comprising an outer wall portion connected to the and has the same over-all appearance as the can end 17. side wall and an inner wall portion connected to the end However, the angle of slope of the outer side wall 23, panel, said wall portions being joined by an intermediate which is identified by the letter C as opposed to the letter bend for increasing resistance to inwardly directed radial A of the can end 17, ranges from 4 to 12. Also, the deflection and bulging and buckling of the end panel, said side wall sloping downwardly and radially inwardly from said curl, and said inner wall portion sloping upwardly and radially outwardly at an angle greater than the slope of said outer wall portion.

2. The can end of claim 1 wherein the slope of said outer side wall is at an angle between 4 and 12.

3. The can end of claim 1 wherein the slope of said outer side wall is at an angle between 7 and 10.

4. The can end of claim 1 wherein said intermediate bend is a sharp bend having an internal radius of no greater than 0.025 inch.

5. The can end of claim 1 wherein said intermediate bend is a sharp bend having an internal radius of approximately 0.012 inch.

'6. The can end of claim 1 wherein an upper part of said inner wall portion contacts said side wall.

7. A can incorporating the can end of claim 1 wherein said can end is secured to a can body with said side wall being telescoped within said can body and said curl forming part of a double seam securing said can end to said can body.

References Cited UNITED STATES PATENTS 1,756,585 4/1930 Curtis 220-67 2,205,685 5/ 1940 Conner 22072 2,309,341 1/1943 Condon 22066 2,971,671 2/1961 Jhakman 22066 3,229,847 1/1966 Fox 22066 3,288,342 11/1966 Tinker 22067 THERON E. CONDON, Primary Examiner.

JAMES R. GARRETT, Assistant Examiner. 

